CommandTimeline_Outcome constructor Null safety

1. spine_client
2. command_log.pb
3. CommandTimeline_Outcome
4. CommandTimeline_Outcome const constructor

CommandTimeline_Outcome enum

1. Constructors
2. CommandTimeline_Outcome
3. Values
4. howHandled
5. substituted
6. notSet
7. Properties
8. hashCode
9. index
10. runtimeType
11. Methods
12. noSuchMethod
13. toString
14. Operators
15. operator ==
16. Constants
17. values